This application is the U.S. National Phase under 35 U.S.C. xc2xa7371 of International Application PCT/JP99/00641, filed Dec. 2, 1999.
The present invention relates to a device for gel-coating seeds and more particularly to a device which continuously and simultaneously coats a plurality of seeds with a gelling agent, wherein the device is applicable to a whole size of seeds.
Conventionally, there is a well-known device for coating seeds with a gelling agent mixed with nutriment, medicament or the like, which has a plurality of nozzles into which respective seeds are dropped and the gelling agent is filled. The process of gel-coating a seed in each of the nozzles is performed as follows:
First of all, a little amount of gelling agent is discharged into the nozzle so as to form a gel-membrane blocking in a bottom tip of the nozzle. Next, a seed is dropped into the nozzle so as to be caught with the gel-membrane. Then, the gelling agent is more filled into the nozzle so as to thicken the gel-membrane, thereby gel-coating the seed. This gel-coated seed falls from the bottom tip of the nozzle with its empty weight.
Incidentally, the gel-coated seeds from the nozzles fall into hardener solution. The gel-coated seeds are conveyed in the hardener while their gel-coats are hardened. Then, the gel-coated seeds are carried into a rinsing unit such that the hardener stuck on the gel-coated seeds is rinsed out. Thus, the gel-coated seeds are finished to be products.
The nozzle unit of the conventional device for gel-coating seeds as mentioned above has a drawback such that each nozzle is supplied into its bottom tip with a gelling agent, which is substantially horizontally discharged from a longitudinal or lateral side of the nozzle. If the pressure for discharging the gelling agent is insufficient, it may happen that the gel-membranes, i.e., the gel-coated seeds cannot be formed.
Besides, the gel-coated seeds fall from the bottom tips of the nozzles with their empty weight. If the seeds are very small, it may happen that the seeds do not acceptably fall from the nozzles.
The present invention is a device for gel-coating seeds having a nozzle into which a gelling agent is filled and a seed is charged and held in the gelling agent to form a gel-coated seed which is then allowed to fall. The nozzle vertically penetrates a nozzle casing which is divisible up and down. A joint surface through which the upper and lower parts of the nozzle casing are joined together is disposed higher than a gel-filled portion of the nozzle. A gallery for the gelling agent is formed on the joint surface. The lower part of the nozzle casing is formed therein with a passage from the gallery to be connected to the gel-filled portion below the gallery. Due to such a structure, the gelling agent is charged downward into the gel-filled portion of the nozzle. Therefore, the pressure for discharging the gelling agent is increased to surely form a gel-membrane for receiving the seed.
The gallery for the gelling agent may be compactly formed into a groove which is circular centering a horizontal section of the nozzle, when viewed in plan, thereby enabling the gelling agent to be sufficiently stored around the nozzle.
The passage from the gallery to the gel-filled portion of the nozzle may comprise a pair of paths arranged in opposite to each other with respect to an axis of the nozzle to communicate to the gel-filled portion. More than one of the pair of paths may be disposed at regular intervals. Therefore, the gelling agent is evenly dispersed and filled into the gel-filled portion of the nozzle from all the paths, thereby forming an even gel-membrane.
Furthermore, a nozzle intermediate portion is formed into an open/close portion that can be switched between opening and blocking states. Compressed air can be charged into a portion of the nozzle between the open/close portion and the gel-filled portion. The air is charged synchronously with the blocking state of the open/close portion. Therefore, this air pressure surely makes the gel-coated seeds, even if they are granular and light, fall from the nozzle.
Incidentally, the open/close portion of the nozzle may be constituted by reciprocally inserting an open/close member, in which a part of said nozzle is formed, into the nozzle casing forming the nozzle. In the same nozzle casing, an air chamber is formed so as to communicate with a portion of the nozzle between the open/close portion and the gel-filled portion. A piston interlocking with the open/close member is reciprocally inserted into the air chamber so as to pressure-charge air into the nozzle. Therefore, the above-mentioned structure wherein gel-coated seeds are dropped by air-pressure can be obtained.
Furthermore, if there are disposed a plurality of the nozzles, a means for integrally reciprocating all the open/closing members and the pistons provided to the respective nozzles may be provided so as to exert the effort of the compressed air to all the nozzles simultaneously.